Lidocaine-induced methemoglobinemia: a clinical reminder.

Methemoglobinemia is a rare condition in which the iron in hemoglobin is stabilized in the ferric (Fe(3+)) form, making it unable to bind oxygen and leading to tissue hypoxia and possibly death. The condition may be hereditary or acquired, the latter resulting from ingestion or application of common oxidizing agents such as lidocaine. As management of methemoglobinemia depends on prompt recognition, clinicians who administer or prescribe oxidizing agents must be aware of the clinical symptoms of methemoglobinemia, including cyanosis, pulse oximetry values that do not respond to increased oxygen delivery, and altered mental status. Currently, methylene blue is the drug of choice for the management of methemoglobinemia.

Angioedema in a 47-year-old woman with hypocomplementemic urticarial vasculitis syndrome.

Hypocomplementemic urticarial vasculitis syndrome (HUVS) is a type III hypersensitivity reaction characterized by urticaria with persistent acquired hypocomplementemia. Although HUVS is uncommon, it is important for physicians to be familiar with this disease, as the initial presentation is often life-threatening angioedema. The author reports the case of a 47-year-old white woman with a history of HUVS. She presented to an outpatient clinic complaining of a rash and difficulty swallowing. Urticaria and angioedema were diagnosed. The patient was given epinephrine in the clinic and then transferred to the hospital. Laboratory testing confirmed urticaria, and the patient was given intravenous methylprednisolone sodium succinate and an additional dose of epinephrine. After 1 week, the patient's angioedema improved.